Tuple

2 definitions found

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  TUPLE
       
          Toyohashi University Parallel Lisp Environment.  A parallel
          Lisp based on KCL.
       
          ["Memory Management and Garbage Collection of an Extended


          Common Lisp System for Massively Parallel SIMD Architecture",
          Taiichi Yuasa, in Memory Management, IWMM92, Springer 1992,
          490-507].
       
          (1994-11-08)
       
       

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  tuple
       
          In {functional language}s, a data object containing two or
          more components.  Also known as a product type or pair,
          triple, quad, etc.  Tuples of different sizes have different
          types, in contrast to lists where the type is independent of
          the length.  The components of a tuple may be of different
          types whereas all elements of a list have the same type.
          Examples of tuples in {Haskell} notation are (1,2),
          ("Tuple",True), (w,(x,y),z).  The degenerate tuple with zero
          components, written (), is known as the unit type since it has
          only one possible value which is also written ().
       
          The implementation of tuples in a language may be either
          "{lifted}" or not.  If tuples are lifted then (bottom,bottom)
          /= bottom and the evaluation of a tuple may fail to terminate.
          E.g. in Haskell:
       
          	f (x,y) = 1    -->    f bottom = bottom
          			      f (bottom,bottom) = 1
       
          With lifted tuples, a tuple pattern is refutable.  Thus in
          Haskell, {pattern matching} on tuples is the same as pattern
          matching on types with multiple constructors ({algebraic data
          type}s) - the expression being matched is evaluated as far as
          the top level constructor, even though, in the case of tuples,
          there is only one possible constructor for a given type.
       
          If tuples are unlifted then (bottom, bottom) = bottom and
          evaluation of a tuple will never fail to terminate though any
          of the components may.  E.g. in {Miranda}:
       
          	f (x,y) = 1    -->    f bottom = 1
          			      f (bottom,bottom) = 1
       
          Thus in Miranda, any object whose type is compatible with a
          tuple pattern is assumed to match at the top level without
          evaluation - it is an {irrefutable} pattern.  This also
          applies to user defined data types with only one constructor.
          In Haskell, patterns can be made irrefutable by adding a "~"
          as in
       
          	f ~(x,y) = 1.
       
          If tuple constructor functions were {strict} in all their
          arguments then (bottom,x) = (x,bottom) = bottom for any x so
          matching a refutable pattern would fail to terminate if any
          component was bottom.